I see myself as part of the Modern movement, a movement which is going through a period of crisis, of questioning, a period which is trying to re-evaluate its role, and which is no longer a revolution but, rather, one which is trying to find a balance recognising the value of the past and the fact that the present and future are built on the past. A critical area is the city and the erosion of the city as a people's place. The only reason for a city is that people meet there; all the actual activities could go on outside cities in new towns, in out-of-city universities and so on. But as a meeting-place, that is what is unique to the city. Traffic and lack of consideration or possibly the demand of a materialistic society have put the city in this critical position.

The first project that I will talk about is one which we did for a major exhibition, which we called 'London as it could be: a study on two axes'. The axis which we took was one which could be called North-South going from Leicester Square and Piccadilly to Trafalgar Square, down Northumberland Avenue and across the Thames to Waterloo Station, picking up what one might call the major squares or spaces in the West End of London and linking the much richer, institutionally richer, North bank with the poorer South bank, economically poorer. The other axis was between Vauxhall Bridge on the Thames, linking it up all the way along the Embankment up to Blackfriars Bridge and the City of London. One of the problems that London has is that all the so-called meeting places of London - Marble Arch, Hyde Park Corner, Leicester Square, Piccadilly Circus, Trafalgar Square and so on - are in fact not meeting places, they are actually traffic junctions or roundabouts. Trafalgar Square is probably the biggest one of all, it is totally inaccessible, and even if you dared to get onto this great space which was once the heart of an empire, you have nothing to do but feed the pigeons. So one could start there and say that it is important for the buildings around the square to actually link onto it. And so we changed the traffic round Trafalgar Square so that the great linear building along its North side, the National Gallery, actually became part of the Square itself. And we then linked both back and forwards from that, back towards Leicester Square with a small pedestrian route, and Piccadilly Circus, and then forward towards the river. We created a series of traffic-free zones by studying the traffic and we recommended that Charing Cross Station should be removed from the heart of the North embankment to the South embankment, to Waterloo Station which is just the other side. So that one would have a free development area on one corner of Trafalgar Square and we would remove what is a hideous bridge, Hungerford Bridge, and we suggested instead a pedestrian bridge linking the North and South and to take people who would get off at Waterloo (which would then become Waterloo and Charing Cross combined) we suggested a shuttle train which is suspended underneath the bridge.

Now many people say that the problem about the Thames is that it's not used in the sense that the Seine is in Paris or other major rivers, because it's too wide. So we suggested a series of floating islands or moored islands in the Thames. Waterloo Station became a great gateway. It would include the final stop of the Paris - London train which would now go through the Channel Tunnel, assuming the Tunnel will be built. So this becomes a great gateway and people would be able to either walk, or take the shuttle train right into Trafalgar Square.

On the other axis we took the so-called Embankment road and rolled it into the river below the water in a tube, and this allows the whole of the Embankment to become a great linear park. And now with the control of the floods with the great floodgates just below Greenwich, there's no longer need for that large wall which cuts off the people from the Thames. We recommended removing the wall along the Embankment and allowing steps to go down into the river so people could be in contact with the Thames, parks, small shops, pavilions and so on. So one would regain the quality of the Thames, I say regain because actually everything we have talked about so far was there in some way or other one hundred years ago. This is just bringing back some of the values that the city had, of course using the technology of the twentieth century and the expression of the twentieth century. In a sense one is looking both back and forwards.

As part of that development we also combined our entry for the National Gallery competition which we had competed for some years back. That already had recommended that Trafalgar Square should either be linked to the National Gallery or alternatively there should be a pedestrian passageway which started at Leicester Square and which would continue downhill - because it is downhill from Leicester Square, it's only two blocks away from Trafalgar Square - and link it to the centre of Trafalgar Square. And the National Gallery would form a form of gateway to Trafalgar Square, balancing on the opposite side the spires of the great church, which is in fact the only good building round Trafalgar Square, St. Martin's In The Field. The National Gallery is a moderately good building, though actually it changes its mind continually along its facade, it's not a great building.

So the building itself is strongly rooted in the planning problems, the linking of those three key squares, and examining the problem of planning also allowed us to realise that we didn't need to put offices to support the National Gallery - because economically the National Gallery couldn't afford to build its own building and therefore asked for the developers to produce offices - but we realised if we could encourage the flow (and our experts told us we had done that) sufficiently, you could have shops instead along the base of that extension to the National Gallery, giving again another activity to Trafalgar Square which is a public activity. And it is this erosion of public activities which I shall come back to a number of times during this talk. We also in visual terms not only linked as a gateway the National Gallery extension to Trafalgar Square, but we also created a tower where there would be a restaurant at the top of it which balanced in height and in position, in fact, St. Martin's In The Field at the east end.

When we examined this in urban terms, we actually found there's an exact relationship between the National Gallery dome, which is a rather poor small dome marking the entry into the National Gallery, and equidistant to our own suggested tower, an equidistance to St. Martin's In The Field and equidistance to Nelson's column. So there's quite a simple geometry which without labouring the point, helped to tie that part of London to mark it both on the ground and on the sky which helped develop the skyline. Many people said to us 'the problem with your scheme is that it does not build in the same manner, it does not harmonise with the other buildings around'. As I've already mentioned, other buildings around, with the exception of that one building, the church, are all mediocre, and the whole question of harmony, the word harmony, is an interesting one. Actually, if we examine historically what harmony means, I think we'll find that though harmonious, each great building round a great square represents its period.

If we take Piazza della Signoria, for instance, which has been built over in, I suppose, the last one thousand years, and we start with the wonderful Palazzo della Signoria started in 1100 and completed about 1300, 1400, in the medieval style; next to that you have the wonderful Uffizi Gallery by Vasari (Vasari didn't imitate the great Palazzo); and next to that is, one hundred years later, the great colonnade for the small open outdoor sculpture space; and then there are further medieval buildings. All these buildings represent very truthfully the period in which they were built. Yet as we became more conscious of the past, so Vasari aimed the whole of his Galleria at the tower of the Palazzo, of the thirteenth century Palazzo. But he didn't imitate it. In fact, to be absolutely accurate, he did build one small piece of the Palazzo and extended it, and when he built that little bit of the Palazzo he did imitate it because it was actually a piece of the Palazzo. When he came to his own building he talked in his own High Renaissance language. And in fact there's only one poor building on that piazza and that's one nineteenth century building which was developed in a sort of pastiche style and it stands out as the one poor building in that square. And the same could be said of San Marco in Venice and so on. In other words, the point that I'm making is that harmony is also by contrast as well as by building in the same style. I don't think you can suddenly imitate a past style.

Moving on to Centre Pompidou, a competition we won in 1971 with Renzo Piano. Here again, we started by looking at the brief or the program and questioning it. And we felt very strongly that what was needed was not another elite museum but rather a people's place. Now that part of Paris at that time lacked completely open spaces. It's changed lately with the development of Les Halles. So we decided to have the building on only about one third of the land, the rest being a great piazza. And we tried to create a building for all people, for all activities, for an overlapping of activities, because we felt that if you wished to draw more people to a museum, the answer is to have a more complex programme. There was already going to be a library and we added many other activities, in fact we had a group called the non-program activities group led by an architect who was actually searching for activities which you could do, which would draw people of all ages, of all creeds, of all colours. And so the building became a sort of framer, a climbing frame and we tried to glorify the skyline of Paris and the excitement of using the building, as well as the wonderful museum and books that were going to go into it, by glorifying movement - in other words, by creating a great escalator where people could go up and down, with views across Paris, by creating corridors on the outside, and by saying this is really a general purpose building because the activities will last much less long than the building. That's very likely, at least as we see it. We keep on seeing building being transformed. The activities get changed but buildings have a much longer life. So the building itself is rooted in flexibility as well as upon the enjoyment of the person who uses it. In other words one is looking for a longer life of buildings. So here you have five massive floors with no columns, no vertical interruptions, everything's on the outside, the services are put on the outside, the movement is put on the outside of the building, so as to leave these great playing-fields of spaces which can respond to changing needs. In fact, the museum decided to come in very late in the game, for a while it was removed from our program, then it came in. I think this is typical of the way the twentieth century deals with institutions and where they need to be placed. One of the criticisms of Centre Pompidou has been that many people just arrive, use escalators and go along the corridors. I think this is fine. This is part of living; it's the enjoyment of using a building as well as the enjoyment of going to see the activities well housed within that building. Inside the building, the museum has lately been changed. A new curator has come; he's appointed his own Italian architect, Gae Aulenti, to do the interiors. I think this is absolutely correct. If you're going to offer flexibility, which all our buildings do, and of course our view of architecture is our specific view, it's our view, I welcome other views. If you're going to have this view of architecture, then the person who uses those buildings, the people responsible for those buildings, must change it as needs change.

The building is not just a machine. It is very much a craft-made object. Here again there's been much attack upon technology, the whole syndrome of inhuman buildings. There is a slide showing the column and beam and the junctions and so on, which I think very clearly indicates the craftsmanship quality of all the pieces. Yes, it's mass-produced. In other words there are a few hundred major brackets, a few thousand column junctions and so on. And the forces are clearly defined, i.e. the compression, the tension elements are separated, and language is created which is easily legible. That's part of our form of architecture. In other words, we're trying to create an architecture which, if you look at it, you can understand what each piece does, how it acts, whether people walk on it, whether people go up, whether it glorifies the activities of the people but also glorifies the pieces, the pieces which are designed, very much like Gothic cathedral structures are designed. In other words, yes you need a flying buttress, you certainly didn't need to glorify a flying buttress in the way that the fifteenth century and fourteenth century did. And we too, we didn't have to have such an expressive building but we felt this would be a way of breaking down the scale and the grain in such a way that the people could understand the building as well as the activities inside. On the side of the piazza there is the people's activities.

On the side of the road where all the cars go along, there are the mechanical services, brightly coloured, each service having its own colour and therefore adding colour to the city.

The people who enter the building are but a few of the total number of people who use the piazza. And in fact one of the major activities which I am a great lover of is watching of people, and people come to Centre Pompidou to watch other people as well as to go into the building. And so you have these wonderful forms of groups which you can see, looked down from the building on the piazza, people looking up from the piazza at the building and the people climbing up and down the escalators. And so you have music and dance and fire-eaters and magicians and all the street activities which the French are so good at, being performed outside the building. So the building is really a people's building.

Going on from Centre Pompidou to a more technical building, the building we built called Inmos in Wales for our first manufacturing centre in this country for the microchip seven years ago. This again was a one-off building but with a brief that asked for the possibility of extending that building and also to have that building in different sites. I say one-off in the sense that it was a specific client, and he foresaw the fact that whatever he would start with, the demand of the microchip would be such that you would need to be able to respond to both the increased demand and the changing way that we make the microchip. And so we created a building where the services are on the roof - they more or less have to be because they can't be under the building because of vibration.

But we put the services in the centre of the building, and once we had all these mechanical services - and there are a vast number of mechanical services which you need to support the manufacturing of the microchip, and the key thing of the microchip is the fact that it has to be manufactured in a totally clean space, in the cleanest of clean spaces, dust-free, vibration-free, etc. So once this is on the roof we put the services in the structure, which we called the spine; so the mechanical services were above the building, and below at the ground level we created a great street, a sort of semi-private semi-public street where people could come out of the laboratories where they were making these communication chips, change out of their clothing which they have to do for their clean areas, and relax for a few minutes or a few hours.

The superstructure of the whole mechanical services was used also to suspend cables from, to hold the roof up, which allows a large span. So again one had a great horizontal space, rather like Centre Pompidou, which had great flexibility because there was just a floor solid and a roof which was suspended from the servicing structure.

The walls themselves were also flexible. And here again its part of the problem which I've been interested in for a long time. That is, not only should there be flexibility on plan and section but also flexibility in elevation. And this question of how one can create an urban object - I suppose one could call it a work of art - and yet transform, and it is this question of transforming and change, of permanence and transformation, out of which these sort of aesthetics, which I'm interested in, evolve. I think also you have to try and find a system where the client can more or less have his openings like window openings, or solids or elements and so on, where he likes, he can expand, contract and so on. And so we're looking for a much more ad hoc elevation. I rather like jazz. We're looking for a building which can take improvisation but which still has a rhythm and that's what nearly all the buildings which we work on are about. The play of light and shadow which gives a certain rhythm, which allows the user to change the bits and pieces, so the building has a certain feeling of incompleteness. Again, one of the elements here is in this hit-and-miss system of windows, translucent, transparent or solid, it can be interchanged wherever one wants, and also the very careful detailing of the exposed steel structure on the outside, and the fact that the great beams which are suspended from the central mast are tied down at the end, and those tie-downs are not expressed as columns but literally as ties and each junction is carefully considered.

In the same vein as the Inmos building for microchips is another building we did in Princeton, U.S.A., for PA Technology. Here, the change was a different type. They're not making microchips, but what they do is research for business organisations into market products with a high technological content, electronics, acoustics, biotechnology and so on. So the departments are changing all the time. So here again we took the services and put them out on the roof, created a different form of superstructure, a form of A-frame, and suspended the roof from it. Both the Inmos building and the PA Technology building are gateway buildings. PA Technology was the first building on a science campus which we laid out, and they wanted this building to be seen across the flat plains of New Jersey from a distance, and this also helped. So there's also a visual content as well as the more straightforward functional needs.

Coming to the last building which is Lloyds and which is the major building which we have built in London, Lloyds as an institution in the City is the second biggest institution after the Bank of England and it wanted a headquarters building which stated that this was a building of a company which has been in the City of London for two hundred and fifty years, three hundred years, insuring, and therefore it had a quite specific image. Lloyds has already occupied three buildings this century. So this will be the fourth. So it wanted a building that would see it well into the next century, which meant great flexibility. It tried to give us a very specific brief about the sort of growth patterns it was likely to follow, because it realised it had made mistakes before. But of course, like all growth patterns, within days of having a very specific brief showing the growth patterns, changes started to take place. So we had very little idea whether Lloyds would be increasing in its use of the building. In fact, the second part of Lloyds brief was they wanted a trading floor which had what they called 'totality of vision' which means basically that everyone can see what another person is doing. We therefore created a building which had as large a floor plan as possible because we felt that not only functionally was it necessary to give them for use but also, in a sense, that the streets around Lloyds are very tight streets, full of rather exciting corners and medieval in structure. And we created a building which basically was a doughnut building, a building with a series of platforms round a great soaring atrium in the centre. And these platforms are floors which go all the way round, which again are column-free, and all the services removed into service towers on the outside. These platforms can be either used as trading floors or they can be used as offices, so that if the trading expands, so they remove the partitions from the offices and trading goes on on those floors. We started with the idea of having one major floor and one gallery. We're now opening up gallery four for trading. So again, anyone who says flexibility is not relevant, I think it is extremely relevant and becomes more relevant as we move into the next century.

We wanted to create a building which was rich in its articulation because we felt that it had to tie to the buildings around which were mainly Victorian; also, in response to some of many rather boring one-liner type buildings of the middle twentieth century of which London has an unfair number. We wanted a building where the eye was led from element to element, from piece to piece. And so, in a sense, architecture which is this mixture of function and art which has really two clients, the passer-by and the user, buildings have to respond to these two specific aspects of the art and the technology, not that I think that they can actually be separated. In fact I think they're the same in the end, there's just a stronger element part of one or the other, in each thing in each part that you try to tackle. So the building is designed in aesthetic terms to be articulated, highly legible, highly understandable. It consists of a simple rectangle, the great atrium, and then six towers which are outside the building which mark the skyline and which in a sense state Lloyds HQ. And these towers have the servant elements (to use Kahn language) and again it's a question of life expectancy.

It is our belief that the life of a building can be calculated often in hundreds of years but the life of mechanical services - such as elevators for instance - is probably five to twenty five years. Those parts have to be easily accessible. So we put them on the outside.

That's the functional reason. It gives a great flexibility internally and it gives you a very, very efficient usable space. But of course, in architectural terms it gives you the maximum play of light and shadow, the maximum play of masses, and this gives you something to manipulate the relation to the environment around, and the way that the eye is led from vertical to vertical as you approach the building. The building responds to the north, to the high buildings of the city towers, and south to the lower buildings specifically the beautiful Leadenhall Market. Interestingly enough, Leadenhall Market which is a Victorian steel and panel structure, has much of the same language that we have. The roots of both our building and the engineering structures of that period, the architectural structures of the nineteenth century, are very much the same roots.

Anyone looking at the building can see the different layers. From the outside you have these towers with external lifts which give a wonderful view of London. You have the staircases, prefabricated. The toilets which arrive complete are just capsules which are dropped into place. The air-conditioning ducts, the triple-glazing - the glazing itself holds the air-conditioning and it brings up an old idea (in fact Le Corbusier talked about it, about the breathing building) and the air conditioning is no longer only in ducts, it's actually between the panes of glass. This makes it both more efficient in energy terms, but also it allows you to get very close to the outside of the building, i.e. the glass, without feeling either hot or cold.

As you move in from there you see the expressed structure, then the translucent glass. We used a specially-designed transparent glass to give the building a sparkle. We call it a 'wall of light'. The idea was with a minimum amount of light inside and outside the building it would sparkle rather like a chandelier. We did a lot of research with PA Technology to try to find the right sparkle glass, rather than black. The atrium, the great central atrium which I think is the highest space, internal space in Europe, with its glass barrel roof, has inside it not only a series of floors but an escalator which the traders use which is all lit up - and this escalator in a sense is a bit like the Centre Pompidou escalator on the outside but this time it's much more private, and this gives it a life and a dynamism to the inside. The materials of Lloyds are materials which are one might say long-life. Centre Pompidou is a very cheap building whilst Lloyds is an HQ building with a good budget and materials are translucent glass, stainless steel and a concrete frame. The concrete frame is highly articulated to minimise weathering problems and very carefully detailed - in fact we went to the U.S. to study with I.M. Pei, for instance, how to pour concrete, and so on. And the parts of Lloyds are again each one very carefully considered, each one is both using industrial techniques - in other words, the whole idea of the architect controlling the process. I believe that the architect is in danger of becoming a fashion designer because he does more and more of beautiful large sketch drawings of the total building and without appreciating the process of building it, the way that a factory works which produces the parts. That's where the craftsmanship comes in. An architect has got to control the manufacturing process.

The final slide here is a whole myriad of small elements within the building - the handrail, the light, the number, the escalator part, the junctions - and it tries to express and explain the decoration if you like as well as the function. I've had many clients who have gone to see Centre Pompidou for instance and say 'I don't understand why Centre Pompidou needed an architect. It only needs an engineer'. The point that one's making is actually each decision you have a million different ways of solving it. And it is the way that you solve that problem, the craftsmanship and the creativity that you bring to that, which makes the difference between a building which is a straightforward shall-we-say engineering response (engineering in its minimum form) or whether it is a real design response.